Halohydrocarbons are used commercially as solvents, pesticides, refrigerants, fire-resistant oils, ingredients of elastomers, adhesives and sealants, electrically insulating coatings, plasticizers, and plastics etc. Many halohydrocarbons have specialized uses in industry. For example, polyvinyl chloride, commonly known as PVC, may be made by polymerization of vinyl chloride monomer which in turn may be made from ethylene dichloride. PVC may be the third-most widely-produced plastic, after polyethylene and polypropylene. PVC is widely used in construction because it is durable, cheap, and easily worked.
The halohydrocarbons may be made by direct chlorination of hydrocarbons using chlorine gas. For example, ethylene dichloride may be made by direct chlorination of ethylene using chlorine gas made from the chlor-alkali process. The production of chlorine gas and caustic soda by electrolysis of aqueous solutions of sodium chloride or brine is one of the electrochemical processes demanding high-energy consumption. The total energy requirement is for instance about 2% in the USA and about 1% in Japan of the gross electric power generated, to maintain this process by the chlor-alkali industry. The high energy consumption may be related to high carbon dioxide emission owing to burning of fossil fuels. Therefore, there is a need for an economical and environmentally friendly process to make halohydrocarbons.